A5006480989- Microwave Engineering and Waveguides
- Crystallization and Solubility Studies
- Radio Frequency Integrated Circuit Design
- X-ray Diffraction in Crystallography
- Superconducting and THz Device Technology
- Advanced Battery Materials and Technologies
- Advancements in Battery Materials
- Semiconductor materials and devices
- Advanced Sensor and Energy Harvesting Materials
- Metal-Catalyzed Oxygenation Mechanisms
- Advanced Antenna and Metasurface Technologies
- Electrospun Nanofibers in Biomedical Applications
- Semiconductor Quantum Structures and Devices
- 3D IC and TSV technologies
- Metal complexes synthesis and properties
- Metalloenzymes and iron-sulfur proteins
- Advanced Battery Technologies Research
- Semiconductor Lasers and Optical Devices
- Dielectric materials and actuators
- Electromagnetic Compatibility and Noise Suppression
- Polymer composites and self-healing
- Conducting polymers and applications
- Microbial metabolism and enzyme function
- Porphyrin and Phthalocyanine Chemistry
- Advanced Memory and Neural Computing
Stanford University
2023-2025
Korea Advanced Institute of Science and Technology
2022-2023
Seoul National University
2018-2020
Dongguk University
2004-2006
University of Virginia
1995
Cornell University
1992-1993
An elastic printed circuit board (E-PCB) is a conductive framework used for the facile assembly of system-level stretchable electronics. E-PCBs require conductors that have high conductivity, stretchability, tough adhesion to various components, and imperceptible resistance changes even under large strain. We present liquid metal particle network (LMPNet) assembled by applying an acoustic field solid-state insulating composite as conductor. The LMPNet conductor satisfies all aforementioned...
Abstract Over the past decade, conductive hydrogels have received great attention as tissue-interfacing electrodes due to their soft and tissue-like mechanical properties. However, a trade-off between robust properties good electrical has prevented fabrication of tough, highly hydrogel limited its use in bioelectronics. Here, we report synthetic method for realization mechanically tough with modulus. We employed template-directed assembly method, enabling arrangement disorder-free,...
Abstract Modulating lithium metal deposition is vital for the realization of stable and energy‐dense Li–metal batteries. Ionic liquid (IL) has been regarded as a promising electrolyte additive uniform Li because its cation moiety forms lithiophobic protective layer on protuberant tips. Despite recent advances in ILs batteries, rational designs IL additives are still their infancy, further improvement required. Here, new class self‐assembled based design molecule enabling high‐performance...
Mechanically tough and self-healable polymeric materials have found widespread applications in a sustainable future. However, coherent strategies for mechanically self-healing polymers are still lacking due to trade-off relationship between mechanical robustness viscoelasticity. Here, we disclose toughening strategy elastomers crosslinked by metal-ligand coordination. Emphasis was placed on the effects of counter anions dynamic behaviors polymer networks. As coordinating ability anion...
Abstract Dielectric elastomer actuators (DEAs) offer versatile applications including haptics, soft robotics and smart lenses. However, due to the lack of conductive electrodes with low modulus high stretchability, their use is limited by nonsolid electrodes, hindering integration other systems. In this study, transparent patternable solid achieving actuation performance comparable a commonly used non‐solid counterpart (e.g., carbon grease), stretchable conducting polymer composed PEDOT:PSS...
The electrolyte plays a critical role in lithium metal batteries. In particular, ion solvation profoundly impacts key properties and battery performance. this study, we systematically investigate solvation-property relationships series of electrolytes with different solvent-diluent ratios. Through potentiometric techniques that measure the relative free energies electrolytes, find weaker correlates larger clusters, lower ionic conductivity diffusion coefficient, superior electrochemical...
Novel functions emerge from novel structures. To develop efficient catalytic systems for challenging chemical transformations, chemists often seek inspirations enzymatic catalysis. A large number of iron complexes supported by nitrogen-rich multidentate ligands have thus been developed to mimic oxo-transfer reactivity dioxygen-activating metalloenzymes. Such efforts significantly advanced our understanding the reaction mechanisms trapping key intermediates and elucidating their geometric...
We develop a platform for recyclable polyurethane-based thermosets fabricated by photopolymerization. Tunable mechanical properties and 3D printing are demonstrated, with mild acid-catalyzed degradation enabled hemiacetal linkages.
A 2-D MESFET utilizing sidewall Schottky contacts on either side of a very narrow 2-d electron gas channel is described. Record transconductance 295 and 130 mS/mm have been achieved at room temperature in 1.0 0.5 micron wide devices, respectively. We also present accurate current-voltage capacitance-voltage models. These models implemented into AIM-Spice which was used to simulate DCFL inverter ring oscillator circuits. The simulations predict power-delay product less than 0.1 fJ/gate...
Abstract Atom‐transfer chemistry represents an important class of reactions catalyzed by metalloenzymes. As a functional mimic non‐heme iron enzymes that deliver oxygen atoms to olefins, we have designed monoiron complexes supported new N ‐donor chelates. These ligands take advantage heme‐like conformational rigidity the π‐conjugated molecular backbone, and synthetic flexibility tethering donor groups for additional steric electronic control. Iron generated in situ can be used carry out...
Hydrogen bonding-assisted polarization is an effective strategy to promote bond-making and bond-breaking chemical reactions. Taking inspiration from the catalytic triad of serine protease active sites, we have devised a conformationally well-defined benzimidazole platform that can be systematically functionalized install multiple hydrogen bonding donor (HBD) acceptor (HBA) pairs in serial fashion. We found increasing number interdependent mutually reinforcing HBD-HBA contacts facilitate...
A new double modulation-doped AlGaAs/InGaAs heterostructure with a graded composition in the InGaAs quantum well (QW) has been designed and electrically characterized. An QW rectangular-like potential profile presence of two dimensional electron gas is obtained by two-step grading In composition, which results broad symmetric distribution even under various voltages. The Hall measurement shows very high mobility 7230 cm2/V s an sheet density 4.1×1012/cm2 at room temperature. To our...
We report the 94 GHz CPW branch-line bandpass filter for planar integrated millimeter- wave circuits. The basic idea is to use coupler as a transversal filtering section by connecting coupled ports open load stubs and taking isolated port output node. exhibits an insertion loss of 2.5 dB with 11.7 % 3 relative bandwidth at center frequency return better than -18 frequency. designed fabricated shows good performance millimeter-wave
The effective lowering of the Schottky barrier height in In0.52Al0.48As diodes under reverse bias conditions is investigated by fitting experimental reverse-bias I-T relationships to thermionic-field emission theory. This can be explained without assuming a lack Fermi level pinning. electron mass deduced experimentally from procedure ranges 0.072m0 0.087m0, which comparable published data. largely dependent on temperature range current. amount mass, but not zero-field height.
This paper describes a new GaAs-based surface-micromachined microstrip line supported by dielectric posts and with an air gap between the signal ground metal. type of post air-gapped microstripline (DAML) structure was developed using surface micromachining techniques to provide easy means air-bridge connection lines achieve low losses in millimeter-wave frequency band wide impedance range. Each DAML is fabricated length 5 mm. By elevating from substrate technology, loss can be reduced....
In this paper, we develop a new type of band-reject filter, which provides the practical usefulness dielectric-supported air-gapped microstriplines. The filter is composed signal line 10-μm height in order to reduce substrate dielectric loss and post size 20 × μm2 that supports line. fabricated band- reject has measured band 46.6 dB at 45 GHz pass 1.7 60 GHz. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 1–4, 2005; Published online InterScience (www.interscience.wiley.com)....
전류제한 에피 구조를 적용하여 MINT에서 개발한 최적화된 공정방법으로 InP Gunn 다이오드 칩을 제작하고 이용하여 MINT의 조건을 패키지 하였다. 또한 제작된 다이오드의 RF 특성을 측정하기 위하여 2체배 구조의 W-band 도파관 FTO(Fixed Tuned Oscillator)를 설계 및 제작하였다. 패키지된 다이오드는 ceramic ring, Au plating stud와 lid 그리고 Maltese cross로 구성되어있다. 측정된 20개의 최대 전류가 399 mA의 전류특성을 가지고 92.9～94.78 GHz에서 발진하였고 11.8～17.8 dBm 의 출력전력을 얻었다.